I can't ssh to my Amazon AWS Ubuntu instance using a newly created user and a key pair?

Question

I created a user called grader to my instance and gave it sudo permission, also I switched the password in /etc/ssh/sshd_config to be off.

I generated a key pair in my local machine and added the public key to the instance. When I try to access the instance using the DEFAULT user provided by Amazon AWS and my generated keys it works

ssh -i "udacityLinux" ubuntu@ec2-18-218-9-117.us-east-2.compute.amazonaws.com

but when I try the same using the grader user I get this error:

ssh -i "udacityLinux" grader@ec2-18-218-9-117.us-east-2.compute.amazonaws.com
grader@ec2-18-218-9-117.us-east-2.compute.amazonaws.com: Permission denied (publickey).

How can I fix this to be able to login using my grader user?

Answer 1

You seem to have a misunderstanding about the public key you upload to the server.

This key must be stored in the file ~/.ssh/authorized_keys for every user that should be identified by this key.

This path ~/.ssh/authorized_keys is equivalent to your current user directory, if you are logged in as grader user, that path will point to:

/home/grader/.ssh/authorized_keys

In case you are logged in as ubuntu user, that path will point to:

/home/ubuntu/.ssh/authorized_keys

So for now you could copy the key file with:

sudo cp /home/ubuntu/.ssh/authorized_keys /home/grader/.ssh/

Then set the correct owner and permissions:

sudo chown grader:grader /home/grader/.ssh/authorized_keys
sudo chmod 0600 /home/grader/.ssh/authorized_keys

Keep in mind that now you accept all keys that you might have enabled for the user ubuntu for the user grader as well.